All poultry carcasses entering the processing environment are contaminated with microorganisms, some with pathogenic bacteria such as Salmonella. Fecal matter and dirt are the main sources of this contamination. As a result of such contamination, poultry is typically washed at any of several steps during the process of converting a live bird to an edible food product. Such washing aims to remove dirt, offal, blood, viscera, other debris, and microbes from the poultry. Removing or reducing microbes aids the safe storage and consumption of poultry, yet many existing washing procedures fail to significantly reduce the microbe burden on poultry. The potential for poultry skin to become cross-contaminated is worsened by the ability of all types of microorganisms to adhere within only 15 seconds of contact. Once in the processing environment, a significant number of carcasses can become cross-contaminated with pathogens during handling, scalding, mechanical processing, and chilling. Current methods for many of these procedures also fail to significantly reduce the microbe burden on poultry.
Water used for washing or these other procedures is often used repeatedly over time, which provides yet another opportunity for spreading, rather than reducing, microbial burden on poultry. For example, the water becomes contaminated with organic matter and microbes from the poultry, and the organic matter provides nutrients for microbial growth in the water over time or through additional use. These microbes can grow on and contaminate additional poultry and processing equipment. In particular, water left untreated in a submersion bath tends to decontaminate poultry early in a shift but contaminates poultry later in the shift. In fact, such water has been identified as a potential source of coliform, E. coli and Salmonella contamination or cross contamination during poultry processing. Salmonella and other microorganisms are generally undesirable to the poultry, the water, and can cause buildup on all water contact surfaces of slime or biofilm, which requires frequent cleaning to remove.
Microbial contamination or cross contamination of poultry via water continues to be a major concern for poultry processors and end users. Although washing, cooling, or heating poultry carcasses with water can reduce potential contamination, the processing water can also serve as a source of contamination or cross contamination. If pathogenic microorganisms in water are not removed, inactivated or otherwise controlled, they can spread to other poultry, potentially contaminating them. Further, handling or processing steps that pool many individual poultry parts tend to increase the risk that a single contaminated item may contaminate the entire lot. Immersing or spray-washing poultry in fresh water can help reduce surface populations of microorganisms. However sterilization by repeated washing, even with sterile water, cannot be achieved because microorganisms within tissues of poultry remain in place.
The addition of antimicrobial agents to wash or process water can inactivate vegetative bacteria cells in water, helping avoid contamination. Ideally, an antimicrobial agent or compound used in such a system will have several important properties in addition to its antimicrobial efficacy. The compound or agent should have no technical effect on the final food product. Residual activity implies the presence of a film of antimicrobial material which will continue to have antimicrobial effect which may require further rinsing of the food product. The antimicrobial agent can also be odor free to prevent transfer of undesirable odors onto food stuffs. If direct food contact occurs, the antimicrobial agent should also be composed of food additive materials which will not affect food wholesomeness, nor affect humans should incidental ingestion result. In addition, the antimicrobial agent can be composed of naturally occurring or innocuous ingredients, which are chemically compatible with the environment and cause no concerns for toxic residues within the water.
In the past, poultry wash or process waters have generally been treated with chlorinated compounds, organic acids, acidified sodium chlorite, trisodium phosphate, or ozone. Generally, these materials are effective in reducing microbial contamination on poultry. However, the use rate of these antimicrobials is very high because they are not effective at low concentrations or they tend to be rapidly consumed by the high organic load included with the poultry. Excessive chlorination of food processing water with hypochlorite has prompted concern over production of toxic or carcinogenic organochlorine compounds and other by-products.
Further, the efficacy of conventional antimicrobial agents on the surface of poultry is often limited. For example, it has been reported that, generally, concentrations of more than 4 wt-% of organic acids or of 5 to 10 wt-% of trisodium phosphate are required to effectively reduce contamination of poultry skin by S. typhimurium. Antimicrobial agents such as peroxides or lactic acid can result in discoloring, bleaching, or bloating of poultry tissue.
The EPA approved a peroxyacetic acid-based composition in 1996 for controlling microbial growth and reducing biofilm formation in fruit and vegetable transport or process waters. From a historical perspective, peroxyacetic acid has been used for food contact surface sanitizing, aseptic packaging and medical device cold-sterilization. In addition to its biocidal properties, the environmentally-friendly decomposition byproducts and good stability in the presence of organic matter helped gain acceptance of this technology among fruit and vegetable packers, handlers, and processors. Such conventional peroxycarboxylic acid compositions typically include short chain peroxycarboxylic acids or mixtures of short chain peroxycarboxylic acids and medium chain peroxycarboxylic acids (see, e.g., U.S. Pat. Nos. 5,200,189, 5,314,687, 5,409,713, 5,437,868, 5,489,434, 6,674,538, 6,010,729, 6,111,963, and 6,514,556).
Nevertheless, there remains a need for improved antimicrobial compositions for addition to waters used for washing or processing poultry.